1. Field of the Invention
This invention relates generally to tubes which are inserted into the body. More particularly, the present invention relates to medical tubing such as gastric tubes which include an antireflux valve which is adapted to allow the injection of fluids through the tube without removal of the valve.
2. Prior Art
Medical tubes such as are commonly used for insertion into the body of a patient to administer or collect fluid are in common use in hospitals. A particular device of this nature is a nasogastric tube which is inserted through the nasal passage of the patient into the patient's stomach or intestine to remove fluid from the patient or to administer medications or nutritives.
For example, nasogastric tubes of this type may be used post operatively to prevent pooling of liquids in the stomach during the patient's recovery. Often, gastric tubes of this type are formed with dual lumens, including a primary suction lumen and a secondary vent lumen which communicate with each other at the distal end or tip of the tube by means of a small orifice therebetween. The suction lumen also includes a plurality of side holes formed therethrough near the distal tip of the catheter for allowing suctioned fluids to pass into the catheter from the stomach.
As is shown in U.S. Pat. No. 4,735,607 to Keith, Jr., nasogastric tubes often include a branching tube (identified as element 23 in the Keith, Jr. reference) which communicates with the secondary vent lumen of the tube and includes a check valve therein which functions to inhibit the flow of reflux fluid through the vent lumen and out of the tube to contaminate the patient area.
When in use for removing fluids from the stomach, the upper or proximal end of the gastric tube is ordinarily connected through a collector vessel to a vacuum pump system. Stomach fluids are then drawn through the side holes in the distal end of the tube and into the collector vessel. Often however, the side holes become clogged with stomach debris, or more seriously, by the inadvertent drawing of soft stomach wall tissue thereinto.
To help prevent blockage of the tubing side holes, the vent lumen of the dual lumen tube permits atmospheric air to be drawn through the small orifice at the distal end thereof into the suction lumen. This prevents over suctioning which could otherwise damage the stomach wall tissue. As is evident, proper operation of the double lumen tube depends on the continuous availability of atmospheric air to the suction openings through the small orifice between the suction lumen and the vent lumen at the distal end of the tube.
Unfortunately, double lumen nasogastric tubes frequently do not operate as intended, and stomach pressure becomes greater than atmospheric pressure allowing gastric reflux, or leakage, to occur through the vent lumen. This over pressure can be caused by the patient coughing, by over filling the stomach with air, or by external pressure on the stomach. Leakage of fluids due to gastric reflux can cause significant problems such as wound contamination, infections, etc., and significant time in clean up of the patient area by the hospital staff.
One very effective solution to the problem of gastric reflux has been to place an antireflux valve, such as that shown in the above-cited prior art patent to Keith, Jr., into the gastric tube at the proximal end of the vent lumen. The antireflux valve allows entrance of atmospheric air into the vent lumen, while preventing the passage of reflux fluid therepast. However, it is often necessary to inject fluids directly into the patient's stomach through the venting lumen for the purposes cf irrigation, medication, nutrition, etc. In the past, such procedures have required the removal of the antireflux valve to allow attachment of a syringe or the like for injecting fluid through the vent lumen. This necessity is less than satisfactory in that it often allows contamination of the patient area and/or bacterial ingress to occur through the vent lumen.